Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
While the burgess or farmer called out under the levy saw in military service nothing but a burden to be undertaken for the public good, and in the gains of war nothing but a slight compensation for the far more considerable loss brought upon him by serving, it was otherwise with the enlisted proletarian. Not only was he for the moment solely dependent upon his pay, but, as there was no Hotel des Invalides nor even a poorhouse to receive him after his discharge, for the future also he could not but wish to abide by his standard, and not to leave it otherwise than with the establishment of his civic status, His only home was the camp, his only science war, his only hope the general--what this implied, is clear.
When Marius after the engagement on the Raudine plain unconstitutionally gave Roman citizenship on the very field of battle to two cohorts of Italian allies en masse for their brave conduct, he justified himself afterwards by saying that amidst the noise of battle he had not been able to distinguish the voice of the laws. If once in more important questions the interest of the army and that of the general should concur to produce unconstitutional demands, who could be security that then other laws also would not cease to be heard amid the clashing of swords?
They had now the standing army, the soldier-class, the bodyguard; as in the civil constitution, so also in the military, all the pillars of the future monarchy were already in existence: the monarch alone was wanting. When the twelve eagles circled round the Palatine hill, they ushered in the reign of the Kings; the new eagle which Gaius Marius bestowed on the legions proclaimed the near advent of the Emperors.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/4-06-marius-revolution-drusus-reform.asp?pg=14